% This function defines the operation of two-input multiplexer.
% INPUT: 
%       a1: the stochastic sequence of the first input for the mux; 
%       a2: the stochastic sequence of the second input for the mux;
%		a3: the stochastic sequence of the selection input for the mux;
% OUTPUT: 
%       a: the stochastic sequence of the output for the mux.
% Copyright @ The authors, 2012.
function a= mux2(a1,a2,a3)          
   a=a1.*(1.-a3)+a2.*a3;